Rotor blade



May 1967 E COVINGTON ETAL 3,316,976

ROTOR BLADE F11ed Dec] 3 1965 5 Sheetssheet May 2, 1967 F11ed Dec C' E COVNGTON ETAL ROTOR BLADE 5 Sheetssheet 2 M y 1967 c E COVINGTON ETAL ROTOR BLADE 3 Sheetssheet 5 INVENTORS (g) said trailin ed e member bein c]0ser to said s ar and of reater chordwise len th at the root end of Said rotof blade than at the outboard end,

h) Said s ar bein of constant Section alon the feater ortion of its length With increasing chord to thickness ratio outwardly a10ngits length, and

(i) the length of Said bade that includes the increa3- in chord to thickness ratio ortion of said s ar rovidin a substantia1 art of the eective lift roducin force of said blade` UNITED STATES PATENTS 1 94978S 3/1934- Cierva 1701S9 5 2,293,801 8/l94z Caldwe11 170 19 2,609,883 9/19 2 Daland 17019 

1. AN INTEGRALLY CONSTRUCTED ROTOR BLADE COMPRISING: (A) INBOARD AND OUTBOARD SECTIONS, (B) SAID OUTBOARD SECTION HAVING AN INCREASING CHORD TO THICKNESS RATIO PROCEEDING FROM THE INNERMOST END OF SAID OUTBOARD SECTION TO THE TIP OF SAID BLADE AND PROVIDING A SUBSTANTIAL PART OF THE EFFECTIVE LIFT PRODUCING FORCE OF THE ROTOR BLADE, (C) SAID INBOARD SECTION HAVING ITS LEADING EDGE SUBSTANTIALLY IN LINE WITH THE LEADING EDGE OF SAID OUTBOARD SECTION, AND THE INNERMOST PART OF SAID INBOARD SECTION HAVING A LESSER CHORD LENGTH THAN SAID OUTBOARD SECTION. 